Structural and mechanical properties of double wall carbon nanotubes

Narrow diameter double wall carbon nanotubes can be grown with high yield by catalytic chemical vapor deposition. Double walled carbon nanotubes are the molecular analogs of coaxial cables. The external tube protects the internal tube from its environment and isolates the electric conductor of sub-nanometer dimension over micrometer long distances. While it is still particularly difficult to grow tubes of controlled helicity, inelastic light scattering is a powerful tool to find the helicity of narrow diameter internal tubes and explore their mechanical properties. We have examined the inelastic light scattering spectrum of narrow double walled carbon nanotubes to specify their helicity and to study their mechanical stability under hydrostatic pressure.